Crystal Castles don’t like us to know what they’re doing. They play live in disorienting strobe-lit darkness, and they release MP3s on the internet without giving us any idea what they’re planning on doing with these songs. So here, without context, is “Plague,” their latest bit of bloodthirsty gothed-out dance music. It will doubtless sound amazing the next time you see them in some dank cavern of a venue.